14453-57-7Relevant articles and documents
Oxidative coupling of 1-naphthols over noble and base metal catalysts
Maphoru, Mabuatsela V.,Heveling, Josef,Pillai, Sreejarani K.
, p. 99 - 106 (2014)
Bismuth-promoted platinum catalysts were tested for the oxidative coupling of 2- and 4-substituted 1-naphthols at different temperatures and ambient pressure. The principal final products are the 3,3'-substituted 1,1'-binaphthalenylidene-4,4'- diones and the 4,4'-substituted 2,2'-binaphthalenylidene-1,1'- diones, respectively. Hydrogen peroxide was used as the oxidant. Only naphthols with electron-donating substituents reacted. The corresponding binaphthalenyl diols can be considered as reaction intermediates. Yields of up to 99% were obtained from 2-methyl-1-naphthol as the starting material within 20 minutes. Probably for steric reasons, the diol is the final product obtained from 2-ethyl-1-naphthol. For 4-methoxy- 1-naphthol the outcome is determined by the reaction temperature. At 25 8C the expected 1,1'-dione is the major product, whereas at 60 8C 1'-hydroxy-4'-methoxy-2,2'-binaphthalenyl- 1,4-dione is formed; the loss of one methoxy unit and the preservation of the hydroxy group can be explained by the competitive cleavage of one of the two O-Me bonds at higher temperature. Unpromoted platinum and a range of other metallic catalysts, including gold and Raney nickel, were also found to be active. The products obtained are brightly colored solids that could be used as dyes. The method described is truly catalytic and environmentally benign. The potential of the technique justifies further research to expand on the applicability of this novel method.
Mesostructured vanadia-alumina catalysts for the synthesis of vitamin K3
Florea,Marin,P?l??anu,Nea?u,Parvulescu
, p. 29 - 35 (2015/01/30)
Liquid-phase selective oxidation of 2-methylnaphtalene to the vitamin K3 was investigated on a series of mesostructured vanadia-alumina catalysts with different V/Al ratios (0.1-1). They were prepared by the co-precipitation of ammonium metavanadate and aluminum nitrate at pH 5 and characterized by XRD, Raman, TG-DTA, elemental analysis and adsorption-desorption isotherms of nitrogen at -196 °C. The influence of the catalyst composition and calcination temperature upon the physico-chemical properties were closely investigated in relation with the catalytic performances. The result of this investigation indicated the catalysts containing a higher vanadium loading and calcined at 300 °C as the most active. Thus, the VAl07 catalyst led to a selectivity in vitamin K3 of 54% for a conversion of 2-methylnaphtalene of 76%. Such an activity corresponded to mixtures where metavanadate (Raman line at 940 cm-1) and decavanadate (Raman line at 990 cm-1) species were the most abundant. No lines of V2O5 (around 705 cm-1) were detected in the catalysts calcined below 600 °C.
4,4'-Binaphthylidene-1,1'-diones - Colour and Structure
Kral, Andreas,Laatsch, Hartmut
, p. 1401 - 1407 (2007/10/02)
Synthesis and properties of various 4,4'-binaphthylidene-1,1'-diones are described.The UV spectra of the deep red to purple diones may be calculated on the base of substituent increments.The experimental values of the analyzed substituents can be reproduced using PPP calculations with satisfying accuracy, which makes it possible to predict also absorption maxima of hitherto unknown 4,4'-binaphthylidene-1,1'-diones.Keywords: 4,4'-Binaphthylidene-1,1'-diones, Phenol Oxidation
